1. Field of the Invention
The present invention generally relates to a dielectric resonator device, and more particularly, to a dielectric resonator device which includes inner conductors provided within a dielectric member, and signal input and output electrodes formed on the outer surface of the dielectric member together with an outer conductor. The present invention relates to a mounting arrangement for mounting the dielectric resonator device of the above described type on a mounting substrate.
The dielectric resonator device which includes inner conductors formed within a dielectric member or dielectric block, and an outer conductor formed on the outer surface of the dielectric block is used, for example, as a band-pass filter or the like in a microwave band region.
The dielectric resonator device of this kind is normally formed by a resonator device provided with lead terminals, in which, by inserting signal input and output pins into bores of the dielectric block formed with inner conductors, the pins can be used as leads for signal input and output.
However, in order to meet an ever increasing demand for compact size in recent years, for making it possible to mount the dielectric resonator device on the surface of mounting substrates such as printed circuit boards, etc. in a manner similar to the mounting of other electronic parts, there has also been conventionally employed a mounting arrangement in which electrical connection and mechanical connection are simultaneously effected by providing signal input and output electrodes directly on the surface of the outer face of the dielectric block for soldering between said electrodes and the mounting substrate, for example, as disclosed in Japanese Patent Application Tokuganhei No. 4-9207 filed earlier by the present applicant.
For mounting a dielectric resonator device of a surface mounting type with respect to a mounting substrate, in a manner similar to the mounting of other electronic parts of the surface mounting type such as chip resistors, chip capacitors, etc., the so-called reflow soldering process is employed. This process uses solder paste (cream solder) which is preliminarily applied onto conductor patterns on the mounting substrate, and the dielectric resonator device is placed thereon for temporary fixing, whereby the soldering is effected by locally heating the entire mounting substrate or the dielectric resonator device portion to be mounted.
Such reflow soldering is a superior mounting method suitable for an automatic mounting machine of electronic parts, and also for attaching very small electronic parts. However, in the case of the dielectric resonator device, there is such a peculiar point as compared with other general chip resistors, chip capacitors, surface mounting type variable resistors or surface mounting type transformers, etc., that there are employed signal input and output electrodes formed to be separated, in an island form, from an outer conductor provided on the outer surface of the dielectric block of the resonator device. Therefore, in spite of the fact that the dielectric resonator device has a larger overall size as compared with other general chip parts, there are several disadvantages. For example, solder bridges tend to be formed between the signal input and output electrodes and the outer conductor because the clearance therebetween is small. Also the signal input and output electrodes are mainly formed on the bottom face of the dielectric block opposing the mounting substrate, and moreover, not only the signal input and output electrodes, but the outer conductor of a comparatively large area present on the surface facing the mounting substrate must also be connected simultaneously. Thus, mounting of the dielectric resonator device becomes difficult as compared with that of the ordinary chip parts, etc.